Enzymatic paper and process of making thereof

ABSTRACT

The present invention includes a process for making paper. The process may include the steps of providing pulp fibers in a chest and adding an enzymatic material to the pulp fibers at a storing stage for decreasing cellulose crystals. Furthermore, the process may include adding a strength agent to the pulp fibers at the storing stage.

FIELD OF THE INVENTION

[0001] This invention generally relates to the field of paper making,and more specifically, to an enzymatic prepared paper.

BACKGROUND

[0002] Generally, paper products such as towels and tissues are designedto combine several important attributes. For example, the productsshould have good bulk, softness, absorbency, and strength.

[0003] In the past, many attempts have been made to enhance and increasecertain physical properties of paper products. Unfortunately, stepstaken to increase one property of a paper product may adversely affectother product characteristics. As an example, softness and bulk can beincreased by decreasing or reducing interfiber bonding within the paperweb. However, inhibiting or reducing fiber bonding by chemical and/ormechanical means adversely affects the strength of the product. Achallenge encountered in designing paper products is increasingsoftness, bulk, and absorbency without decreasing strength.

[0004] Accordingly, there is a need for a paper product having improvedsoftness, bulk, and absorbency after undergoing fiber modification whilemaintaining at least the same strength properties.

DEFINITIONS

[0005] As used herein, the term “comprises” refers to a part or parts ofa whole, but does not exclude other parts. That is, the term “comprises”is open language that requires the presence of the recited element orstructure or its equivalent, but does not exclude the presence of otherelements or structures. The term “comprises” has the same meaning and isinterchangeable with the terms “includes” and “has ”.

[0006] As used herein, the term “cellulose” refers to a naturalcarbohydrate high polymer (polysaccharide) having the chemical formula(C₅H₁₀O₅)_(n) and consisting of anhydroglucose units joined by an oxygenlinkage to form long molecular chains that are essentially linear.Natural sources of cellulose include deciduous and coniferous trees,cotton, flax, esparto grass, milkweed, straw, jute, hemp, and bagasse.

[0007] As used herein, the term “pulp” refers to cellulose processed bysuch treatments as, for example, thermal, chemical and/or mechanicaltreatments.

[0008] As used herein, the term “fiber” refers to a fundamental form ofsolid, usually crystalline, characterized by relatively high tenacityand an extremely high ratio of length to diameter, as an example,several hundred to one.

[0009] As used herein, the term “bleached-chemical-thermo-mechanicalpulp” refers to processing cellulosic material with steam, pressure andsodium sulfite or hydrogen peroxide to soften wood lignin between andwithin cell walls. Furthermore, alkaline peroxide bleaching is added tofurther soften and brighten the fibers. The termbleached-chemical-thermo-mechanical pulp may be hereinafter abbreviatedas “BCTMP”.

[0010] As used herein, the term “sulfite pulp” refers to pulp processedchemically with a mixture of sulfurous acid and bisulfite ion.

[0011] As used herein, the term “basis weight” (hereinafter may bereferred to as “BW”) is the mass per unit area of a sample and may bereported as gram per meter squared and abbreviated “gsm”. The basisweight was measured using a test procedure hereinafter described.

[0012] As used herein, the term “specific volume” refers to valuesdetermined as described herein and may be expressed in units of cubiccentimeters per gram.

[0013] As used herein, the term “weight percent” refers to a percentagecalculated by dividing the weight of an element of a mixture by thetotal weight of the mixture multiplied by 100.

[0014] The term “machine direction” as used herein refers to thedirection of travel of the forming surface onto which fibers aredeposited during formation of a material.

[0015] The term “cross-machine direction” as used herein refers to thedirection that is perpendicular and in the same plane as the machinedirection.

[0016] As used herein, the term “tear index” refers to values determinedas described herein and may be expressed as Newton times meter cubeddivided by gram, which may be abbreviated “mNm²/g”.

[0017] As used herein, the term “tensile index” refers to valuesdetermined as described herein and may be expressed as Newton timesmeter divided by gram, which may be abbreviated “Nm/g”.

[0018] As used herein, the term “machine direction tensile” (hereinaftermay be referred to as “MDT”) refers to values determined as describedherein and may be reported as gram-force, which may be abbreviated “g”.

[0019] As used herein, the term “Frazier Porosity” refers to valuesdetermined as described herein and may be expressed as cubic feet perminute divided by feet squared, which may be abbreviated “cfm/ft²”.

[0020] As used herein, the term “absorbency” refers to values determinedas described herein and may be expressed as seconds, which may beabbreviated “sec”.

[0021] As used herein, the term “geometric mean breaking length”(hereinafter may be referred to as “GMBL”) is the measurement of thestrength of a material, generally a fabric or nonwoven web, and may bereported in length measurements, such as meters. The greater thegeometric mean breaking length generally relates to a stronger material.The geometric mean breaking length is calculated by the formula:

GMBL=(MDT*CDT)^(0.5)/BW

[0022] As used herein, the term “wicking” refers to values determined asdescribed herein and may be expressed as gram of liquid divided by gramof material divided by seconds, which may be abbreviated “g/g/sec”.

[0023] As used herein, the term “water capacity” refers to valuesdetermined as described herein and may be expressed as grams of absorbedwater divided by gram of material absorbing the liquid, which may beabbreviated “g/g”.

[0024] As used herein, the terms “permeable” and “permeability” refer tothe ability of a gas to pass through a particular porous material undera prescribed pressure differential. Permeability may be expressed inunits of volume per unit time per unit area, for example, cubic feet perminute per 38 square centimeter of material, which may be abbreviated“cfm”. Permeability was determined utilizing a Textest permeabilitytester sold under the trade designation FX-3300 from the Benninger Corp.and measured in accordance with ASTM D-737-96 and TAPPI T 251 cm-85.

[0025] As used herein, the term “percent solids” refers to the amount ofsolids in a pulp after being formed on a forming fabric but prior todrying. As an example, a pulp having 75 percent solids would consist of75 weight percent of fibers and other solids, and 25 weight percent ofwater.

SUMMARY OF THE INVENTION

[0026] The problems and needs described above are addressed by thepresent invention, which provides a process for making paper. Theprocess may include the step of adding an enzymatic material at astoring stage of a papermaking process to modify the pulp. Furthermore,the process may include adding a strength agent to the pulp at thestoring stage. The enzymatic material may include cellulase andhemicellulase. Moreover, the enzymatic material may further include anenzyme selected from the group consisting of endo-glucanase,cellubiohydrolase, cellubiase, xylanase, and hemicellulase.

[0027] Also, the enzymatic material may further include endo-glucanase,cellubiohydrolase, cellubiase, xylanase, and hemicellulase. The strengthagent may further include a dry strength agent. The dry strength agentmay be selected from the group consisting of starch, polyacrylamide,guar, locust bean gums, and carboxymethyl cellulose. Furthermore, thestrength agent may include a wet strength agent. The wet strength agentmay be selected from the group consisting of polyamide-epichlorohydrin,polyacrylamides, styrenebutadiene latexes, insolubilized polyvinylalcohol, urea-formaldehyde, polyethyleneimine, and chitosan polymers.

[0028] The present invention also includes a paper made from pulpmodified by an enzymatic material at a storing stage of a papermakingprocess. The pulp may be further modified by adding a strength agent tothe pulp at the storing stage. The enzymatic material may includecellulase and hemicellulase. Furthermore, the enzymatic material mayfurther include an enzyme selected from the group consisting ofendo-glucanase, cellubiohydrolase, cellubiase, xylanase, andhemicellulase. Moreover, the enzymatic material may also includeendo-glucanase, cellubiohydrolase, cellubiase, xylanase, andhemicellulase.

[0029] The strength agent may further include a dry strength agent. Whatis more, the dry strength agent may be selected from the groupconsisting of starch, polyacrylamide, guar, locust bean gums, andcarboxymethyl cellulose. In addition, the strength agent may include awet strength agent. The wet strength agent may be selected from thegroup consisting of polyamide-epichlorohydrin, polyacrylamides,styrenebutadiene latexes, insolubilized polyvinyl alcohol,urea-formaldehyde, polyethyleneimine, and chitosan polymers.

[0030] Another embodiment of the present invention is a paper preparedfrom a pulp modified with an enzymatic material and having a greatersolids content after being formed on a forming fabric than a paper notmodified with an enzymatic material.

[0031] A further embodiment of the present invention is a paper preparedfrom a pulp modified with an enzymatic material and having a faster dropabsorbency compared to a paper not modified with an enzymatic material.Moreover, the paper may have higher permeability, higher Z wicking, andgreater water capacity than a paper not modified with an enzymaticmaterial.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032]FIG. 1 is a schematic diagram of a process for making a paperproduct of the present invention.

[0033]FIG. 2 is a front, elevational view of a permeability tester.

[0034]FIG. 3 is a graphical depiction of data comparing the dropabsorbency versus refiner revolutions for four treatments applied tohandsheets.

[0035]FIG. 4 is a graphical depiction of data comparing the specificvolume versus tensile index for four treatments applied to handsheets.

[0036]FIG. 5 is a graphical depiction of data comparing the tensileindex versus refiner rotator revolutions for four treatments applied tohandsheets.

[0037]FIG. 6 is a graphical depiction of data comparing the tensileindex versus refiner rotator revolutions for four treatments applied tohandsheets.

[0038]FIG. 7 is a graphical depiction of data comparing the dropabsorbency versus tensile index for four treatments applied tohandsheets.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

[0039] Referring now to the drawings, wherein like reference numeralsdesignate corresponding structure throughout the views, and referring inparticular to FIG. 1, there is depicted a schematic process for forminga paper product. The process includes the stages of pulping 20, storing40, and paper forming 60.

[0040] The pulping stage 20 processes cellulosic material into pulpusing any suitable means understood by those of ordinary skill in theart, such as mechanical pulping, thermomechanical pulping,chemical-thermomechanical pulping, bleached-chemical-thermomechanicalpulping, or any variations thereof. The pulping stage increases thesurface area of the fibers and promotes greater fiber-to-fiber bondingand strength development, which increases the strength of thesubsequently formed paper. During mechanical pulping, a refiner havingrotating blades may be used to cut, split, and bruise the fibers ofcellulosic material to expose greater amounts of fiber surface area.Increasing the speed of the rotating blades further reduces thecellulosic material creating greater surface area, which will in turnpromote the formation of stronger paper products.

[0041] It is anticipated that wood cellulosic material in all itsvarieties will normally comprise the paper making fibers used in thisinvention. Such cellulosic material may include hardwoods and softwoods.Hardwoods include the woody substance of deciduous trees (angiosperms)and softwoods include the woody substance of coniferous trees(gymnosperms). However, other cellulose materials, such as cottonliners, bagasse, and rayon, may also be used. Furthermore, fibersderived from recycled paper, which may contain any or all of the abovecategories as well as other non-fibrous materials such as fillers andadhesives, may be used for making paper.

[0042] After the cellulosic material is converted into pulp, it is sentto the storing stage 40 prior to papermaking. Generally, the pulp isagitated during storing to create a substantially homogeneous mixture,but no further refinement occurs.

[0043] The enzymatic material and strength agents may be added at thestoring stage 40 and held at conditions appropriate for enzyme activity.Generally, the enzymatic material is added to convert crystallinecellulose to a more amorphous form. Although the Applicants do not wantto be held to any one theory, it is believed that modifying the pulpfrom crystalline to amorphous form will create a more homogenous pulpmixture. This mixture may result in softer, and more bulky and absorbentpaper products.

[0044] The enzymatic material may include cellulase, hemicellulase,cellobiohydralase, and cellobiase. Cellulases are enzymes that degradecellulose into smaller fragments, primarily glucose, and includeendocellulase and exocellulase. Endocellulase may hydrolyze the beta(1-4) bonds randomly along the cellulose chain and exocellulase maycleave off glucose molecules from one end of the cellulose strand.

[0045] Hemicellulase are enzymes that degrade hemicellulose intofragments, such as the sugars xylose, mannose, and galactose and includeendohemicellulase and exohemicellulase. Endohemicellulase randomlycleave the interior bonds of the hemicellulose chain. Many differenttypes exist, which are specific to the different sugar backbones.Exohemicellulase systemically hydrolyze the nonreducing end of thehemicellulose chain. In particular, hemicellulase enzymes includeesterase, xylase, mannase, glucuronidase, and galactase.

[0046] Cellobiohydrolase enzymes systematically cleave cellobiose fromthe nonreducing end of a cellulose chain, while cellobiase enzymescleave cellobiose into two glucose molecules. Cellobiohydrolase enzymepreparations may be produced by growing suitable organisms known toproduce cellulase. The organisms may be bacteria, fungi, or mold.Organisms producing cellulase include:

[0047] Trichoderma, as an example T. reesei; Aspergillus, as an exampleA. niger; Fusarium; Phanerochaete, as an example P. chrysosporium;Penicillium, as an example P. janthinellum and P. digitatum;Streptomyces, as an example S. olivochromogenes and S. flavogriseus;Humicola, as an example H. insolens; Cellulomonas, as an example C.fimi; Bacillus, as an example B. subtilis and B. circulans; Phlebia;Ceriporiopsis; and Trametes.

[0048] One exemplary enzymatic material may include a mixture ofcellulase and hemicellulase produced by submerged fermentation of thefungus Humicola insolens. The main activities of the material areendo-glucanase, cellubiohydrolase, cellubiase, xylanase, andhemicellulase. This material is manufactured under the trade designationNOVOZYM 342 by Novo Nordisk Bioindustrials, Inc., 33 Turner Road,Danbury, Conn. 06313-1907. Desirably, about 0.005 to about 2.0 weightpercent of enzymatic material is added to the pulp. More desirably,about 0.10 weight percent of enzymatic material is added to the pulp.

[0049] Strength agents may include wet and dry strength agents. Wetstrength agents may include polyamide-epichlorohydrin, polyacrylamides,styrenebutadiene latexes, insolubilized polyvinyl alcohol,urea-formaldehyde, polyethyleneimine, and chitosan polymers. Onecommercial source of a useful polyamide-epichlorohydrin resins isHercules, Inc. of Wilmington, Del., which markets such resin under thetrade-designation KYMENE 557H or KYMENE 557LX. Desirably, about 0.005 toabout 2.0 weight percent of wet strength agent is added to the pulp.More desirably, about 0.6 weight percent of wet strength agent is addedto the pulp.

[0050] Dry strength agents may include starch, polyacrylamide, guar,locust bean gums, and carboxymethyl cellulose. One commercial source ofa useful carboxymethyl cellulose is Hercules, Inc. of Wilmington, Del.,which markets such agent under the trade-designation CMC. Desirably,about 0.005 to about 2.0 weight percent of dry strength agent is addedto the pulp. More desirably, about 0.05 to about 1.0 weight percent ofwet strength agent is added to the pulp.

[0051] The storing stage 40 may include a blend mix tank 44, a save-allchest 48, a machine chest 52, and a stuffbox 56, although othercombinations may be used. Desirably, the enzymatic material is added atthe blend mix tank 44, the wet strength agent is added at the machinechest 52, and the dry strength agent is added at the stuffbox 56,although they may added anywhere at the storing stage 40. Alternatively,the paper may be made without strength agents by only adding theenzymatic material at the storing stage 40. Desirably, the enzymaticmaterial is added to the pulp fibers prior to the addition of thestrength agents. Desirably, the retention time of the enzymatic materialis from about 25 to about 40 minutes and the temperature, as well asother conditions, should be held at conditions that promote enzymeactivity.

[0052] The pulp is transferred from the storing stage 40 to thepapermaking stage 60. Any suitable papermaking process may be used, butsome exemplary papermaking processes using uncreped-through-air-driedand straight rush transfer technologies are disclosed by U.S. Pat. Nos.5,048,589, 5,348,620, 5,501,768, 5,399,412, 5,429,686, and 5,725,734,which are hereby incorporated by reference.

[0053] A couple of examples are provided illustrating paper samples madeaccording to the present invention along with experimental data. Thebasis weight of the samples was used to calculate some of the values inthe following tables. Both examples used basis weights determined in thefollowing manner.

[0054] The following method was used to calculate mass per unit area(basis weight) of specimens, which do not require conditioning. Aspecimen of pre-determined size was cut from the sample material and thebasis weight of the specimen was calculated from its weight and area.

[0055] The following materials were used: a balance, standard weights, alevel, a weighing pan, a cutting press, dies, and a ruler. The balancehad a capacity and sensitivity to weigh to about 0.001 gram (g) forspecimens weighing under about 10 g and about 0.01 g for specimensweighing about 10 g and over. One exemplary balance is sold under thetrade designation OHAUS™ GT210 by VWR Scientific Products of SouthPlainfield, N.J. The standard weights had a range from about 10milligram (mg) to about 100 g. Exemplary standard weights may beobtained from VWR Scientific Products. If a level was not supplied withthe balance, than desirably a sealed glass vial was utilized. Theweighing pan was of a size large enough to hold the specimen and toprevent the specimen from hanging over the pan. Desirably, the minimumdie size for a single specimen will be 4.5±0.1 inch (in.) by 4.5±0.1 in.(114±3 millimeter (mm) by 114±3 mm). However, if multiple smallerspecimens were used to meet the minimum area desired, then any knownsize die would be appropriate. The ruler was graduated in 0.1 in. or 1mm increments.

[0056] Test specimens were obtained from areas of the sample that werefree of folds, wrinkles, or any distortions making these specimensabnormal from the rest of the test material. Desirably, all specimenshad a minimum area of at least 20 in.² (130 cm²) or a number of smallerdie-cut specimens were taken from different locations in the sample witha minimum total area of 20 in.² (130 cm²). The specimens were preparedby cutting within ±1% of the desired size, (e.g., a specimen cut 20 in.²will have an allowable tolerance of ±0.2 in.²). Consequently, thecompleted data should include the size of the specimen measured if notspecified in the product specifications. Furthermore, the procedureprevented dirt or other foreign material on the specimen. A minimum ofthree random specimens were tested for each material for deriving a meanbasis weight.

[0057] Each specimen was weighed with the following procedure. After thecalibrating the balance, the weighing pan was placed on the balance andthe balance tared. The specimen was placed in the weighing pan so noportion of the specimen hung over the edge of the balance. The weight ofthe specimen was recorded to the nearest 0.001 gram if the specimenweighed less than 10 g and to the nearest 0.01 gram if the specimenweighed 10 g or more.

[0058] The basis weight of the samples were calculated by firstdetermining the area of the sample in square inches. Unknown specimenareas were determined by measuring the length and width to the nearest0.01 in. Afterwards, the weight of the specimen measured in grams wasdivided by the area. This value was multiplied by a factor to obtain thedesired units. The following formulas and factors were used to calculatethe basis weight:

Area of specimen (in.²)=Length×Width

[0059] Calculation of basis weight:[Weight(g)/Area]xFactor Conversionfactors:

[0060] g/m2=1550

[0061] g/yd2=1296

[0062] lb/2880 ft2=914.31

[0063] oz/yd2=45.72

EXAMPLE 1

[0064] The following are examples of handsheets made at variousrefinement rates and with different additive combinations. Four batchesof pulp were created by mechanically refining sulfite bleached softwoodproduced from a Kimberly-Clark Corp. mill at Everett, Washington at fourdifferent rotator revolutions, namely, 100, 500, 1000, and 2000revolutions. Afterwards, each batch was mixed with about 10 weightpercent of BCTMP sold by Miller Western Corp. located at Edmonton,Alberta, Canada.

[0065] Next, portions from each batch were separated and treated withone of four additive treatments having different combinations ofenzymatic material and/or strength agents as depicted below in Table 1.TABLE 1 Materials Included In The Treatment Treatment Number NOVOZYM 342KYMENE CMC 1 no yes no 2 no yes yes 3 yes yes no 4 yes yes yes

[0066] The enzymatic material used was about 0.1 weight percent of aNOVOZYM 342 enzymatic material, the wet strength agent used was about0.6 weight percent of a KYMENE agent, and the dry strength agent usedwas about 0.15 weight percent of a CMC agent. The weight percent ofthese additives was in relation to the total weight of the pulp mixture.During additive treatment, the mixtures were maintained at a temperatureof about 43 degrees Celsius, a pH between about 6.5 to 7.5, aconsistency of about 3 percent, and agitated for about 35 minutes. Thereaction time of the enzymatic material was about 35 minutes, thereaction time of the wet strength agent was about 10 minutes, and thereaction time of the dry strength agent was about 5 minutes.

[0067] Afterwards, ten handsheets were prepared from each treated pulp.The handsheets were prepared by pressing about 45 gsm of pulp for about30 seconds at about 308 kiloPascals.

TESTS

[0068] The prepared handsheets were subjected to several tests, namely,specific volume, tear index, tensile index, Frazier Porosity, andabsorbency. All test data points except absorbency in Table 2 werecalculated by taking the mean of ten sample results. Absorbency wascalculated by taking the mean of five sample results.

[0069] The specific volume was determined by measuring the thickness ofthe paper and dividing by the measured paper's basis weight. Thethickness of the paper was determined with a procedure conformingessentially to TAPPI Standard T 411 om-89. The procedure deviated fromthe TAPPI Standard by measuring the thickness of five specimens ratherthan ten TAPPI specimens and conducting three measurements rather thanfive TAPPI measurements.

[0070] The tear index was calculated by dividing the tearing load by thesample basis weight. The tearing load measures the toughness of amaterial by measuring the work required to propagate a tear when part ofa specimen is held in a clamp and an adjacent part is moved by the forceof a pendulum freely falling in an arc.

[0071] The following method was used to determine the tearing load ofthe handsheets. This method determined the average force required topropagate a tear starting from a cut slit in the material being tested.The higher the number, the greater the force to tear the specimen.

[0072] This procedure is specific to a falling-pendulum (Elmendorf-type)instrument. Desirably, the tester is equipped with a pendulum that has adeep cutout (recessed area) on the pendulum sector andpneumatically-activated clamps. The tester used was sold under the tradedesignation Lorentzen and Wettre brand, Model O9ED. This tester may beobtained from Lorentzen Wettre Canada Inc., Fairfield, N.J. 07004.

[0073] In addition to the tester, a specimen cutter was used capable ofproviding 63.0±0.15 mm (2.5±0.006 in.) specimens. It is recommended thatthe specimens be cut no closer than 15 mm from the edge of the materialand the specimens be taken only in areas that are free from folds,creases, and crimp lines. The handsheet specimens were cut to 63±0.15 mmby 73±1 mm and placed facing up in the same direction. Additionalequipment included a 50 g weight.

[0074] No conditioning of specimens was conducted prior to testing. Thetests were conducted in a standard laboratory atmosphere of 23±1° C.(73.4±1.8° F.) and 50±2% relative humidity.

[0075] The number of plies needed for the test results to fall between20 to 60 on the linear range scale of the tear tester was determined.The 63 mm length of the handsheet specimens was run vertically on thetear tester.

[0076] The tester was placed a level surface free from noticeablevibrations and leveled. Afterwards, testing of a specimen was begun byverifying that the power was on. Next, the rotary dial was set to thenumber of plies to be torn. That being done, the number button waspushed and the cutting lever was pushed down. Afterwards, the digitalreadout was verified as correct. Next, the specimen was placed betweenthe clamps with the edge of the specimen aligned with the front edge ofthe clamp. If more than one sheet was tested, the sheets were placedfacing in the same direction. That being done, the clamp button waspushed to close the clamps. Afterwards, a slit was cut in the specimenby pushing down on the cutting knife lever until it reaches its stop.The slit was clean with no tears or nicks. Next, the pend button waspushed to release the pendulum. That being done, the pendulum was caughton the back swing and positioned to the starting position after thependulum traveled one full swing. Afterwards, the pend button wasdepressed to raise the stop once the pendulum was behind it. The valuewas recorded unless the tear line deviated more than 10 millimeters. Ifthe deviation was more than 10 millimeters, the specimen was discardedand a new specimen tested.

[0077] The results were recorded in grams centimeter. The values werereported to the nearest whole number. The following conversion factorswere used with units which had a 1600-gram capacity and did notautomatically convert the test result: # of multiply sheets by  1 sheet16  2 sheets 8  4 sheets 4  5 sheets 3.2  8 sheets 2 10 sheets 1.6 12sheets 1.33 16 sheets 1

[0078] Tensile index of samples was calculated by dividing the sampletensile strength by the sample basis weight. Tensile strength refers tothe maximum load or force (i.e., peak load) encountered while elongatingthe sample to break. The tensile strength was determined with an InstronModel 1122 Universal Test Instrument in accordance with Test MethodTAPPI T 404 cm-82. Each sample was about 2.54 centimeters wide and theinitial separation between the tester jaws prior to elongation was about12.7 centimeters.

[0079] The following test was used to determine the air permeability ofthe handsheets, which was expressed as cubic feet of air per minute persquare foot (ft³/ft²×in). The air, which was drawn through the fabric bya given suction, was measured with an orifice-type flowmeter.

[0080] The equipment utilized in the test included a FrazierPermeability Tester manufactured by Frazier Precision Instrument Co. of925 Sweeney Dr., Hagerstown, Md. 21740. An exemplary FrazierPermeability Tester 100 is depicted in FIG. 2 and includes an inclinedmanometer frame 144. The frame 144 includes an inclined manometer 124,screws 128, a spirit level 130, and a micrometer plunger 132. The tester100 also includes fabric test opening 110, a beveled ring 112, a clamp114, a front portion 116, a motor 118, a suction fan 120, a dial 122, avertical manometer 134, an air orifice sizer 138, a sliding scale 142,and a specimen clamp 148. The specimen clamp 148 has a bottom portion150 and a top portion 152.

[0081] During the testing, the beveled ring 112 was placed over aspecimen to hold it in a smooth condition and with a slight tension inall directions across the fabric testing opening 110. The area of thisopening 110 was about 38.3 cm² (6.99 cm in diameter). The ring 112 washinged at the back of the table and locked in the front portion 116. Themotor 118, which drove the suction fan 120, was adjusted by the dial122. The manometers 124 and 134 were filled with Merriam Red oil havinga specific gravity 0.827, and used to indicate the pressure drop acrossthe test piece and across the orifice 138 for measuring the air-flow.The inclined manometer 124, which indicated the pressure drop across thetest place, was provided with leveling screws 128 and spirit level 130.

[0082] Other equipment used included a flow rate calibration chart, atest plate for calibrating the equipment, and air orifices, havingdiameters of 1.0, 1.4, 2.0, 3.0, 4.0, 6.0, 8.0, 11.0, and 16.0millimeters, and Merriam Red oil refill having a specific gravity of0.827. These items may be obtained from Frazier Precision Instrument Coof 925 Sweeney Dr., Hagerstown, Md. 21740 as well. Additional equipmentincluded a spirit level.

[0083] Tests were conducted in a standard laboratory atmosphere of 23±2°C. (73.4±3.6° F.) and 50±5% relative humidity. A single ply of thespecimens was tested. Opening and closing the doors in the permeabilitytester room was minimized because these actions may cause the manometers124 and 134 to fluctuate erratically.

[0084] Prior to testing, several set-up measures were undertaken besidescalibrating the tester 100. First, the dial 122 was turned all the wayin a counterclockwise direction before plugging the unit in or turningthe unit on. Second, the oil level was verified at zero with the suctionoff in the vertical manometer 134. Third, the sliding scale 142 wasadjusted to obtain the proper zero setting. Fourth, the oil level in theinclined manometer 124 was verified at zero with the suction off. Ifneeded, the micrometer plunger 132 was used to adjust the zero position.Fifth, using a spirit level, the horizontal level of the inclinedmanometer frame 144 was checked. If needed, the screws 128 were adjustedto obtain a level position. Sixth, the air orifice size 138 was recordedon a testing form.

[0085] The testing was conducted as follows. The bottom section 150 ofthe specimen clamp 148, beveled side down, was placed over the opening110. Next, the top section 152 of the specimen clamp 148 was attachedwith the beveled side up to the bottom section 150. Afterward, asingle-ply specimen was placed over the bottom specimen clamp 150. Thatbeing done, the specimen clamp 114 was lowered into position and heldfirmly in place. Next, the unit was turned on. Afterward, the dial 122was turned slowly in a clockwise direction until the inclined manometer124 oil column reached 0.5. The dial 122 was turned slowly whenincreasing the suction because a rapid increase in speed can cause theoil in the vertical manometer to overflow. If the pressure drop on thevertical manometer was less than 3 inches, a smaller orifice was used toget a drop greater than 3 inches. It is usually desirable to have apressure drop between 5 and 20 inches.

[0086] After the inclined manometer 124 oil column had steadied at 0.5level, the level of the oil in the vertical manometer 134 was taken andrecorded on the proper form. The manometers were read at eye level toavoid errors of parallax or distorted readings. The vertical manometerreading was converted to a flow rate in units of cubic feet of air perminute per square foot of sample by using the calibration table.

[0087] The absorbency of the samples measured the rate of water dropabsorption in accordance with TAPPI test method T 432 om-94, whichrecords the times for absorption of a 0.01 mL drop of distilled water.

[0088] The results of the above tests for the sixteen handsheet samplesare depicted in Table 2: TABLE 2 Treatment # 1 Mill Refining Rev. 100500 1000 2000 Specific Volume (cm{circumflex over ( )}3/g) 2.71 2.602.42 2.29 Tear Index (mNm{circumflex over ( )}2/g) 10.42 8.87 8.24 7.43Tensile Index (Nm/g) 27.86 36.36 40.22 44.97 Porosity, Frazier(cfm/ft{circumflex over ( )}2) 158.4 91.7 71.5 41.2 Absorbency (sec) 7.418.2 34.5 50.5 (0.01 ml) Treatment # 2 Mill Refining Rev. 100 500 10002000 Specific Volume (cm{circumflex over ( )}3/g) 2.71 2.51 2.42 2.29Tear Index (mNm{circumflex over ( )}2/g) 12.57 11.57 10.81 9.70 TensileIndex (Nm/g) 29.38 36.29 42.44 46.92 Porosity, Frazier(cfm/ft{circumflex over ( )}2) 177.4 101.5 94.5 45.3 Absorbency (sec)8.3 14.5 36.2 55.7 (0.01 ml) Treatment # 3 Mill Refining Rev. 100 5001000 2000 Specific Volume (cm{circumflex over ( )}3/g) 2.87 2.48 2.392.35 Tear Index (mNm{circumflex over ( )}2/g) 12.01 11.25 10.35 9.68Tensile Index (Nm/g) 27.20 37.50 39.87 44.46 Porosity, Frazier(cfm/ft{circumflex over ( )}2) 180.66 102.18 84.42 32.45 Absorbency(sec) 8.4 22.1 29.2 50.1 (0.01 ml) Treatment # 4 Mill Refining Rev. 100500 1000 2000 Specific Volume (cm{circumflex over ( )}3/g) 2.86 2.532.43 2.22 Tear Index (mNm{circumflex over ( )}2/g) 11.83 10.94 10.338.85 Tensile Index (Nm/g) 30.56 38.93 43.53 47.38 Porosity, Frazier(cfm/ft{circumflex over ( )}2) 163.06 117.24 79.43 32.92 Absorbency(sec) 4.5 10.0 20.5 49.1 (0.01 ml)

[0089] FIGS. 3-7 depict some of the data from Table 2. The figuresillustrate that handsheets having Treatment 4 exhibit faster absorbencyand higher specific volume while having slighter superior strength andtoughness properties than the other treated handsheets.

[0090] In particular, FIG. 3 compares the four treatments at differentrefinement rates. It is clear from the graph that the handsheets havingthe fourth treatment exhibit faster drop absorbency than the othertreated handsheets. Furthermore, FIG. 4 illustrates that the handsheetsmade with Treatment 4 have higher specific volume at most tensile indexranges. These graphs illustrate that Treatment 4 produces handsheetswith greater absorbency and substantially greater specific volume thanthe other treated handsheets, which translates into greater absorbencyand bulk.

[0091] Moreover, FIG. 5 depicts the fourth handsheets having slightlysuperior tensile index attributes at similar refinement speeds, which isa measure of strength, than the three other treated handsheets.Similarly, FIG. 6 demonstrates that handsheets made with Treatment 4have generally the same tear index at a given tear index as the secondand third treated handsheets.

[0092] Overall, handsheets made with Treatment 4 have superiorabsorbency and specific volume while maintaining at least the samestrength and toughness as the other treated handsheets. This is readilyillustrated with regard to drop absorbency by FIG. 7. The handsheetsmade with Treatment 4, which have been treated with enzymes, and wet anddry strength agents, clearly have faster drop absorbency at a giventensile index than the other handsheets.

EXAMPLE 2

[0093] This example compares papers made with varying additiveingredients at a paper manufacturing line. Four separate batches ofpaper were prepared by mixing about 27 kilograms of wet lap pineproduced from a Kimberly-Clark Corp. mill at Mobile, Ala. with about 27kilograms of recycled fiber obtained from Fox River Corp. of Appleton,Wis. for about 20 minutes in a blend mix tank. Afterwards, thetemperature was raised to about 49 degrees Celsius at a pH of about 7.0.In three of the batches, about a 0.1 weight percent of NOVOZYM 342material was added to the fibers and slushed for about two minutes andthe batch was allowed to sit for about 30 minutes.

[0094] The batches were transferred from the blend mix tank to a machinechest and about 6 grams of wet strength agent per about 1000 grams offibers was added to each batch. The wet strength agent utilized was aKYMENE agent sold under the trade designation 557LX by Hercules, Inc.Afterwards the batch was transferred to a stuff box. Optionally, acarboxy methyl cellulose dry strength agent, namely 7MT CMC agentmanufactured by Hercules, Inc., was metered into the stuff box. The CMCagent was added at a concentration of about 0.88 weight solution to thefurnish in the stuffbox. This produced a residence time of about 2.3minutes.

[0095] All batches included the KYMENE agent, but the batches includeddifferent amounts of NOVOZYM 342 material and CMC agent. Table 3 depictsthe amounts used in each batch: TABLE 3 NOVOZYM 342 CMC BATCH (weightpercent) (g CMC/kg pulp) 1 0.0 0 2 0.1 0 3 0.1 1 4 0.1 2

[0096] Each batch was processed into paper sheets by anuncreped-through-air-dried process. The sheets from the batches weresubjected to several tests. The machine direction peak load and GMBLmeasured the strengths of the samples. The wicking and water capacitytested the absorbency levels of the samples. The permeability measuredthe amount of air-flow that will pass through a material at givenconditions per unit of time.

TESTING

[0097] The following test method was used to determine the tensilestrength of the paper sheets. The equipment included a constant rate ofextension (CRE) unit along with an appropriate load cell andcomputerized data acquisition system. An exemplary CRE unit is soldunder the trade designation SINTECH 2 manufactured by SintechCorporation, whose address is 1001 Sheldon Drive, Cary, N.C. 27513. Thetype of load cell was chosen for the tensile tester being used and forthe type of material being tested. The selected load cell had values ofinterest fall between the manufacturer's recommended ranges of the loadcell's full scale value. The load cell and the data acquisition systemsold under the trade designation TestWorks™ may be obtained from SintechCorporation as well.

[0098] Additional equipment included pneumatic-actuated jaws, weighthanging brackets, and precision sample cutter. The jaws were designedfor a maximum load of 5000 g and may be obtained from SintechCorporation. The weight hanging brackets included a flat bracket and an“L” shaped bracket. These brackets were inserted into the jaws duringcalibration or set-up. A precision sample cutter was used to cut sampleswithin 3±0.04 inch (76.2±1 mm) wide. An exemplary sample cutter is soldunder the trade designation JDC by Thwing Albert Instrument Co., ofPhiladelphia, Pa.

[0099] Tests were conducted in a standard laboratory atmosphere of 23±2°C. (73.4±3.6° F.) and 50±5% relative humidity. The two principaldirections, machine and cross, of the material was established. Thespecimens had a width of about 3 in (7.62 cm) and a length in thetesting jaws of about 4 in (10.2 cm). The length of the specimen waschosen either in the cross or machine direction of the material beingtested for determining either the cross or machine direction tensile.Desirably, the length was cut approximately 1.5 inches longer than thejaw spacing used for the test and the test specimens were free of tearsor other defects, and had clean cut, parallel edges.

[0100] The tensile tester was prepared as follows. A load cell wasinstalled for the type of tensile tester being used and for the type ofmaterial being tested. A load cell was selected so the values ofinterest fell between the manufacturer's recommended ranges of the loadcell's full scale value. The separation speed of the jaws was set at10±0.4 inches/minute (25.4±1 cm/minute). The break sensitivity was setat a 65% drop from the peak. Furthermore, the slack compensation was setat 25 grams and the slope preset points were set at 70 and 157 grams.The threshold was set at 2% of the full scale load. Additionally, thejaws were installed on the tester and the tester calibrated by themanufacturer's instructions for the particular tensile tester/softwarebeing used.

[0101] The testing procedure began by inserting the specimen centeredand straight into the jaws. Next, the jaws extending across thespecimen's width were closed while simultaneously excessive slack wasremoved from the specimen. Afterward the machine was started and thejaws separated. The test ended when the specimen ruptured. That beingdone, the results were recorded.

[0102] Once the tensile strength of the specimens were determined in themachine and cross direction, it was important to compensate for thedifferences in basis weight of the samples and for machine directionaldifferences in tensile strength. Compensation was achieved bycalculating a geometric mean breaking length, which is abbreviated“GMBL”. GMBL is calculated as the quotient obtained by dividing thebasis weight into the square root of the product of the machinedirection and cross machine direction tensile strengths.

[0103] When English units of measurement are used, tensile strength ismeasured in ounces per inch and basis weight in pounds per ream (2880square feet). When calculated in metric units the tensile strength ismeasured in grams per 7.62 centimeters and the basis weight is measuredin grams per square meter. It should be noted that the metric units arenot pure metric units because the test apparatus used for testingtensile is set up to cut a sample in inches and accordingly the metricunits comes out to be grams per 3 in. (7.62 cm). Using the abbreviationsMDT for machine direction tensile, CDT for cross machine directiontensile and BW for basis weight, the mathematical calculation of theGMBL is:

GMBL=(MDT×CDT)^(½)/BW

[0104] GMBL in English units=0.060 ×the GMBL in the above defined metricunits.

[0105] The following method was used to determine the absorptioncapacity of the paper products. Equipment items utilized were a capacitytester stand, a water pan, a supply of purified water, a precisionelectronic balance, a weighing dish, a stopwatch, a pair of forceps,paper toweling, hanging clamps, a cutting device, and a thermometer. Thepan was large enough to hold water to a depth of at least (5.08 cm) twoinches. The supply of purified water was distilled or deionized and at astandard laboratory temperature of 23±2° C. (73.4±3.6° F.). The balancewas capable of weighing accurately to about 0.01 g. An exemplary balanceis sold under the trade designation OHAUS™ GT480 by VWR ScientificProducts of South Plainfield, N.J. The weighing dish was large enough tohold the specimen. The stopwatch was accurate and readable to 0.1seconds. An exemplary cutting device is sold under the trade designationTMI DGD by Testing Machines, Inc., Amityville, N.Y. 11701. The die usedwith this device had dimensions of 4 in. by 4 in. ±0.01 in. (10.16 cm by10.16 cm ±0.25 cm). The thermometer was readable to 1.0 ° C.

[0106] Tests were conducted in a standard laboratory atmosphere of 23±2°C. (73.4±3.6° F.) and 50±5% relative humidity. The handling of specimenswas minimized to reduce biasing the test results. The test specimenswere taken from areas of the sample free of folds, wrinkles, or anydistortions, which might have made these specimens abnormal from therest of the test material. Specimens were cut from one sheet to thedimension of 4.0 in. by 4.0 in. ±0.10 in.(10.16 cm by 10.16 cm ±25 cm).

[0107] The testing was performed on a level, solid surface free fromnoticeable vibrations. The balances were allowed the appropriate warm-uptime and tared. Next, the pan was filled with water to a depth of atleast 2 in. (5.08 cm) and a temperature of 23±20° C. (73.4±3.6° F.).

[0108] Each specimen was numbered and weighed and the weight recorded tothe nearest 0.01 gram. Next the stopwatch was started, andsimultaneously, the specimen was placed in the pan of water. Thespecimen was soaked for 3 minutes ±5 seconds. At the end of thespecified time, the specimen was removed by the forceps and attached toa hanging clamp. The specimen hung in a “diamond” shape positionensuring the proper flow of fluid from the specimen. In addition, thespecimen was hung in a chamber having 100 percent relative humidity for3 minutes ±5 seconds.

[0109] Next, the weighing dish was placed on the balance and tared.Afterward, the weighing dish was brought below the hanging specimen andthe clamp was released allowing the specimen to fall into the weighingdish. That being done, the weighing dish and specimen were placed on thebalance and weighed. The weight was recorded to the nearest 0.01 gram.Finally, the wet specimen was discarded and the weighing dish wiped dry.

[0110] Calculations were made as follows. Individual dry and wet weightswere recorded for each specimen to the nearest 0.01 gram. Thus, theabsorption capacity of each specimen was calculated to the nearest 0.01gram as follows:

Absorbent Capacity (g)=Wet weight (g)−Dry weight (g)

[0111] The wicking test involved clamping a specimen and raising a waterbath until it contacts the specimen. An Anderson-Ross Wicking testingmachine, such as those manufactured by Micro Labs, whose address 18EEagle Road, Havertown Pa., is used to measure the XY-direction orhorizontal plane and the Z-direction or vertical plane. The wicking isbased upon the amount of water absorbed in a given direction by thespecimen within an 18 second time period.

[0112] Substantially circular specimens having a diameter of about8.5+/−0.010 centimeters and a thickness ranging from about 0.58 to 0.69millimeter were taken from the tissue products produced as describedabove.

[0113] Five specimen samples were tested by above-described testing foreach product. Thus, each data point in Tables 4 and 5 represents themean of the five samples.

[0114] Table 4 depicts the mean strength of the samples for each batchbelow: TABLE 4 DRY TENSILE g/3 inches GMBL Batch MD CD m 1 7403 55641985 2 7071 5198 1782 3 6700 5554 1918 4 7351 5698 2057

[0115] As can be seen, the samples treated with an enzyme and wet anddry strength agents (Batch 4) exhibit higher mean breaking length thanthe control sample and the sample treated only with the enzyme (Batches1 and 2).

[0116] Table 5 depicts the absorbency and permeability for each batchbelow: TABLE 5 Z Water Capacity Wicking XY Wicking Permeability Batchg/g g/g/sec g/g/sec cfm/38 sq. cm 1 4.00 3.37 1.18 55.6 2 4.16 5.03 1.1772.4 3 4.28 4.09 1.52 72.4 4 4.18 4.45 1.24 72.3

[0117] As can be seen in Table 5, the enzymatic samples from batches 2,3, and 4 exhibit higher capacity, and z wicking, thereby illustratinghigher absorbency than the control batch 1. The enzymatic and dry agenttreated batches 3 and 4 exhibit even higher absorbency, as illustratedby the results in the water capacity and XY wicking. It should be alsonoted that the enzymatic batches 2 and 3 show higher permeability thanthe control batch 1.

EXAMPLE 3

[0118] Paper rolls were made in accordance to the procedure previouslydescribed in Example 2. A control paper roll, which was made insubstantially the same manner as Batch 1 from Example 2, was comparedwith an enzymatic paper roll, which was made in substantially the samemanner as Batch 2 from Example 2. Table 6 compares the two rolls withrespect to the percent solids after vacuum dewatering, but prior tothrough-drying as exemplified in U.S. Pat. No. 5,048,589, which wasincorporated by reference. TABLE 6 Control Enzymatic Rolls Roll TreatedRoll Percent Solids after forming fabric transfer 34% 40% Grams ofWater/Grams of Pulp 1.94 1.50

[0119] The difference in the grams of water per grams of pulp in thecontrol and enzymatic treated rolls results in a reduction of theevaporation load of about 23%. This value was calculated by thefollowing formula:

Reduction in evaporation load=((1.94−1.50)/1.94)*100

[0120] Thus, about 23 percent less energy will be needed to dry theenzymatic sheet to 95% solids. Consequently, the enzymatic treated rollwill save energy during papermaking.

[0121] While the present invention has been described in connection withcertain preferred embodiments, it is to be understood that the subjectmatter encompassed by way of the present invention is not to be limitedto those specific embodiments. On the contrary, it is intended for thesubject matter of the invention to include all alternatives,modifications and equivalents as can be included within the spirit andscope of the following claims.

What is claimed is:
 1. A process for making paper comprising the step ofadding an enzymatic material at a storing stage of a papermaking processto modify the pulp.
 2. The process of claim 1 further comprising thestep of: adding a strength agent to pulp at the storing stage.
 3. Theprocess of claim 1 wherein the enzymatic material further comprisescellulase and hemicellulase.
 4. The process of claim 1 wherein theenzymatic material further comprises an enzyme selected from the groupconsisting of endo-glucanase, cellubiohydrolase, cellubiase, xylanase,and hemicellulase.
 5. The process of claim 1 wherein the enzymaticmaterial further comprises endo-glucanase, cellubiohydrolase,cellubiase, xylanase, and hemicellulase.
 6. The process of claim 2wherein the strength agent further comprises a dry strength agent. 7.The process of claim 6 wherein the dry strength agent is selected fromthe group consisting of starch, polyacrylamide, guar, locust bean gums,and carboxymethyl cellulose.
 8. The process of claim 2 wherein thestrength agent further comprises a wet strength agent.
 9. The process ofclaim 8 wherein the wet strength agent is selected from the groupconsisting of polyamide-epichlorohydrin, polyacrylamides,styrenebutadiene latexes, insolubilized polyvinyl alcohol,urea-formaldehyde, polyethyleneimine, and chitosan polymers.
 10. A papermade from pulp modified by an enzymatic material at a storing stage of apapermaking process.
 11. The paper of claim 10 wherein the pulp isfurther modified by adding a strength agent to the pulp at the storingstage.
 12. The paper of claim 10 wherein the enzymatic material furthercomprises cellulase and hemicellulase.
 13. The paper of claim 10 whereinthe enzymatic material further comprises an enzyme selected from thegroup consisting of endo-glucanase, cellubiohydrolase, cellubiase,xylanase, and hemicellulase.
 13. The paper pf claim 10 wherein theenzymatic material further comprises ebdi-glucanase. cellubiohydrolase,cellubiase, xylanase, and hemicellulase.
 14. The paper of claim 11wherein the strength agent further comprises a dry strength agent. 15.The paper of claim 11 wherein the strength agent further comprises a wetstrength agent.
 16. A paper prepared from a pulp modified with anenzymatic material and having a greater solids content after beingformed on a forming fabric than a paper not modified with an enzymaticmaterial.
 17. A paper prepared from a pulp modified with an enzymaticmaterial and having faster drop absorbency compared to a paper notmodified with an enzymatic material.
 18. The paper of claim 17 preparedfrom a pulp modified with an enzymatic material wherein the paper has ahigher permeability than a paper not modified with an enzymaticmaterial.
 19. The paper of claim 18 prepared from a pulp modified withan enzymatic material wherein the paper has a higher Z wicking than apaper not modified with an enzymatic material.
 20. The paper of claim 19prepared from a pulp modified with an enzymatic material wherein thepaper has a greater water capacity than a paper not modified with anenzymatic material.